The present disclosure relates to fluid-ejection devices intended for washing for example surfaces of parts in motor vehicles and for many other applications.
Fluid-ejection devices are known in the art for washing surfaces of parts in motor vehicles such as for example motor vehicle headlights, lenses, sensors, etc. The main problem found in said devices known so far is that certain areas or parts can not be fully reached. As a consequence, they are not washed, or they cannot be washed properly, e.g. incompletely washed.
A number of alternative solutions have been proposed in the art for addressing the above problems. Examples of said alternative solutions are orientable nozzles and telescopic assemblies.
Prior art orientable nozzles have been shown to be ineffective due for example to the presence of external parts or accessories that may be provided in the path of the liquid being ejected. Again, certain areas or parts cannot be reached and therefore they cannot be washed adequately, while other areas cannot be completely washed.
Known telescopic devices comprise a hollow cylinder, a hollow piston and a nozzle connected to the hollow piston. The hollow piston is driven to be displaced relative to the hollow cylinder as a cleaning liquid is injected therein. Once the hollow piston with the nozzle has been extended, the cleaning liquid is ejected through the nozzle out onto the surface to be washed. While such known telescopic devices have been shown to at least partially overcome the above problems, they are still complex and in some cases they are not able to perform an efficient washing as required.
Examples of telescopic devices for washing surfaces in motor vehicles are disclosed in EP1694541 and EP1506109. The washing device disclosed in EP1694541 comprises a hollow cylinder, a hollow piston and a nozzle connected thereto. The hollow piston is arranged to slide inside the hollow cylinder against a spring as it is driven by a liquid that is fed therewithin. The liquid is then ejected only when the piston has reached a predetermined extended position. The washing device disclosed in EP1506109 comprises an inner hollow cylinder, an outer hollow cylinder fitting into each other and a telescopic nozzle. The inner hollow cylinder comprises an opening for conducting liquid that remains closed as it abuts the outer hollow cylinder. Cleaning liquid is supplied when the telescopic nozzle is completely telescoped.
Another telescopic washing device for projecting a cleaning liquid to a surface of a motor vehicle is disclosed in FR3021014. The telescopic washing device in this case also comprises a fixed member, a movable member and a seal. The movable member is initially retracted and then liquid enters through an inlet port of the fixed member to fill a chamber formed therein. This causes the movable member to be displaced against a spring with an elastically deformable portion of the seal leaning against a first section of the control member such that liquid is still inside chamber under pressure and it is not allowed to flow outside. When the movable member reaches a position where the elastically deformable portion of the seal leans against a second section of the control member having passages, the liquid is allowed to flow through said passages into the control member allowing the liquid to be ejected outside.
The above prior art telescopic washing devices have a number of disadvantages. For example, the washing devices described in EP1694541 and EP1506109 require the stroke of the nozzle to be accurately designed for each specific condition, i.e. a specific type and/or location of the surface to be washed, a specific position and size of the nozzle, the pressure of the liquid that is injected, etc. As a result, such washing devices involve expensive designs and in some cases may be inefficient. In the telescopic washing device disclosed in FR3021014 the control member should be designed according to the stroke to be travelled by the movable member which in some cases may be long resulting again in undesirably complex and capital intensive devices.
There is thus a need for efficient fluid-ejection devices to be used for washing surfaces of parts in motor vehicles and other applications which is in turn simple in structure as well as cost effective in design and manufacturing.